As the development of nanoscale mechanical, electrical, chemical and biological devices and systems increases, new processes and materials are needed to fabricate nanoscale devices and components. This is especially true as the scale of these structures decreases into the tens of nanometers. There is a particular need for materials and methods that are able to duplicate nanoscale patterns over large areas with perfect or near-perfect registration of the pattern features. Block copolymer materials are useful in nanofabrication because they self-assemble into distinct domains with dimensions in the tens of nanometers or lower.
However, existing methods of using block copolymer material suffer from several limitations. Approaches that rely solely on copolymer self-assembly suffer from defects in the patterns. One approach to nanopatterning with block copolymers combines chemical patterning of a substrate by advanced lithographic techniques with the self-assembly of the block copolymers. The chemical pattern directs the self-assembly of the block copolymer, producing perfect or near-perfect duplication of the pattern and registration of the pattern features over a large area.
However, thus far the use of directed self-assembly of block copolymers to replicate patterns has been limited to the replication of periodic patterns. This precludes replicating patterns having irregular features, as would be required by many applications. In addition, the methods and materials used thus far have been limited in that a particular material can be used to replicate only a narrow range of substrate patterns.
What is needed therefore are methods and compositions for replicating patterns containing irregular features in block copolymer films. In addition, it would be desirable to have improved materials and methods providing greater process latitude in replicating periodic and aperiodic patterns.